The LCD (Liquid Crystal Display) possesses advantages of thin body, power saving and no radiation to be widely used in many application scope. It has been widely utilized in, such as mobile phones, PDAs (personal digital assistance), digital cameras, laptop screens or notebook screens. Generally, the liquid crystal display comprises a shell, a LCD panel located in the shell and a backlight module located in the shell. Particularly, the structure of the LCD panel mainly comprise a TFT Array Substrate (Thin Film Transistor Array Substrate), a CF (Color Filter) and a Liquid Crystal Layer. The working principle is that the light of backlight module is reflected to generate images by applying driving voltages to the two glass substrate for controlling the rotations of the liquid crystal molecules.
The Quantum Dots (QDs) material means the semiconductor crystalline grain with grain diameter of 1-100 nm. The grain diameter of the quantum dots material is smaller than or close to the bulk exciton Bohr radius of the appropriate body, and the quantum confinement effect occurs. The level structure is changed from the quasi continuous change of the body material to the discrete structure of the quantum dot material and results in that the quantum dots show particular light emitting performance of the excitation light emission. Along with the size decrease of the quantum dot, the energy band gap increases. Both the required energy of exciting corresponding quantum dot and the energy released by the quantum dot backing to the ground state after the excitation are correspondingly magnified It appears to be the quantum dot excitation and the spectrum blue shift phenomenon of the fluorescence spectrum. By controlling the size of the quantum dot, the narrow full width at half maximum of the light spectrum can cover the entire range of the visible light. For example, the size of the CdSe quantum dot is decreased from 6.6 nm to 2.0 nm. The emission wavelength is blue shifted from the red light range 635 nm to the blue light range 460 nm.
The quantum dot material possesses advantages of controllable emission wavelength, narrow full width at half maximum. The present application technology of the quantum dot material is to utilize a color light emitting layer manufactured with quantum dots of various emission wavelengths to replace the color filter in the liquid crystal display. Thus, the defect of the spectrum distribution of the blue light LED plus yellow phosphor can be resolved to raise the color gamut of the display; however, the color light emitting layer is located at the position which is close to the exterior of the liquid crystal display. The exterior light may excites the quantum dots. Therefore, the contrast of the display in the bright environment will drop and the color shift phenomenon may happen.